A Physiologic Basis for Fibromyalgia

A study of the brain (published on-line Jan 2015) has uncovered an important difference in the processing of pain signals between people with fibromyalgia (FM) and those without FM.(1) Participants with FM had brain imaging with functional magnetic resonance (fMRI) while a blood pressure cuff on their leg created pain at a level (determined by each person) of 40 out of 100.

In response to the blood pressure cuff pain, the 35 FM patients had increased connectivity (compared to 14 subjects without FM) between an area of the brain that senses touch or pain (the somatosensory cortex or S1) and an area that determines how much attention the touch or pain receives (the anterior insula). The degree of connectivity found between these two regions also corresponded to two other important variables:

1. The severity of the FM pain participants experienced before the study.

2. The degree to which FM pain was “catastrophized” as measured by a validated questionnaire.

As reported in Medscape News (2), Lesley M. Arnold, MD, professor of psychiatry and behavioral neuroscience and director of the Women’s Health Research Program at the University of Cincinnati College of Medicine in Ohio, said:

“I think the bottom line is, sometimes the patients with FM experience pain and they feel like physicians aren’t really acknowledging the pain they feel. You can’t see the disorder. There’s no obvious injury. But here we have a study that illuminates that the brain is functioning differently in FM. It legitimizes for patients that there is something different about their brain.”

Follow-up research plans include treating the FM patients with psychotherapy to see if improvement in symptoms corresponds to changes in the connectivity between S1 and the anterior insula.